Heated Mirrors Malfunction

Diagnostic Instructions Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach. Diagnostic Procedure Instructions provides an overview of each diagnostic category. Diagnostic Fault Information

Circuit Number	Circuit Function	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
606	Control	2	1	3	—
2150	Ground	—	1	—	—
607	Control	2	1	3	—
2250	Ground	—	1	—	—
1. Single Heated Mirror Inoperative 2. Both Heated Mirrors Inoperative 3. Heated Mirrors Always On

Circuit/System Description When the HVAC control module receives a rear window defog request from the radio/HVAC controls, the HVAC control module will send a serial data message to the S79D Driver Front Side Door Window Control Switch and S79P Passenger Front Side Door Window Control Switch. Each S79 Front Side Door Window Control Switch provide B+ voltage to the driver outside rearview mirror and passenger outside rearview mirror heating elements. Reference Information Schematic Reference Outside Rearview Mirror Schematics Connector End View Reference Master Electrical Component List Description and Operation Outside Mirror Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References for scan tool information Circuit/System Verification

Engine running
Verify there are no DTCs set. ⇒ If DTCs are set ⇒ Refer to Diagnostic Trouble Code (DTC) List - Vehicle. ⇓ If there are no DTCs set
Verify the E18 Rear Defogger Grid turns ON and OFF when operating the rear defogger switch. ⇒ If the E18 Rear Defogger Grid does not turn ON or OFF Refer to Rear Window Defogger Malfunction. ⇓ If the E18 Rear Defogger Grid turns ON and OFF
Verify the E17D Outside Rearview Mirror Glass-Driver and the E17P Outside Rearview Mirror Glass-Passenger become warm when turning on the rear defogger switch. ⇒ If the E17D Outside Rearview Mirror Glass-Driver or E17P Outside Rearview Mirror Glass-Passenger do not become warm Refer to Circuit/System Testing ⇓ If both the E17D Outside Rearview Mirror Glass-Driver and the E17P Outside Rearview Mirror Glass-Passenger become warm
A fault is not currently present and may be an intermittent condition. Circuit/System Testing
Ignition OFF and all vehicle systems OFF, disconnect the connector at the appropriate E17 Outside Rearview Mirror Glass: E17D Outside Rearview Mirror Glass — Driver = X510 E17P Outside Rearview Mirror Glass — Passenger = X610
Verify a test lamp illuminates between ground circuit terminal 5 and B+. ⇒ If test lamp does not illuminate Repair the open/high resistance on the appropriate circuit or ground connection: E17D Outside Rearview Mirror Glass — Driver = Circuit 2150 E17P Outside Rearview Mirror Glass — Passenger = Circuit 2250 ⇓ If the test lamp illuminates
Engine running, connect a test lamp between the control circuit terminal 8 and the ground circuit terminal 5.
Verify the test lamp turns ON when operating the rear defogger switch. ⇒ If the test lamp is always OFF 4.1. Ignition OFF, remove the test lamp, disconnect the appropriate connector at the S79 Door Switch Panel Control Module: S79D Front Side Door Window Control Switch — Driver = X1 Connector S79P Front Side Door Window Switch — Passenger 4.2. Test the appropriate circuit for an open/high resistance: S79D Front Side Door Window Control Switch — Driver = Circuit 606 S79P Front Side Door Window Switch — Passenger = Circuit 607 ⇒ If an open/high resistance is found, repair the fault on the circuit or ground connection. ⇓ If an open/high resistance is not found. 4.3. Replace the appropriate S79 Front Side Door Window Switch. ⇓ If the test lamp turns ON
Test or replace the E17 Outside Rearview Mirror Glass. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Outside Rearview Mirror Glass Replacement Electrical Relay Replacement